With the development of thin film transistor liquid crystal display (TFT-LCD) technology, the competition among TFT-LCD products is increasingly fierce. The manufacturers constantly attempt new technologies to reduce the cost of their products and to improve the competitiveness of their products. Gate Driver on Array (GOA) technology is a typical representative of these new technologies.
In the GOA technology, a gate switching circuit is integrated on an array substrate so that the gate driver IC can be omitted. Thereby, the material cost can be reduced and the fabrication process can be simplified, and accordingly the product cost can be reduced. In the GOA technology, a signal line of STV (scan driver start vertical pulse) is only connected with the GOA unit of first line (or the GOA units of first few lines). Once electrostatic charges accumulate in the STV signal line, the STV signal line cannot release the electrostatic charges like other signal lines. The first GOA unit may be damaged if the electrostatic charges accumulated in the STV signal line reach a great amount, and thus electrical defect occurs.
A conventional structure for preventing the electrostatic charges from accumulating in the STV signal line is as follows: the STV signal line is connected with a capacitor prior to a connection position of the STV signal line and the GOA unit; and the electrostatic charges are released by a breakdown current generated under a high voltage. As shown in FIG. 1, the capacitor is formed of a gate metal layer that is used to form the STV signal line, a source-drain metal layer that is used to form a VSS signal line and a gate insulating layer. However, in the case of using the above-mentioned conventional structure, signal attenuation may occur due to the charge storage characteristic of the capacitor, which will result in an abnormal display.